A new radiation detector made from graphene

Illustration/photo of the new graphene bolometer, which has a fast response time and works over a wide range of temperatures. With a simple design and relatively low cost, this graphene-based device could be scaled up, enabling a wide range of commercial applications. Credit: Grigory Skoblin

Graphene is a remarkable material: light, strong, transparent and electrically conductive. It can also convert heat to electricity. Researchers have recently exploited this thermoelectric property to create a new kind of radiation detector.

Classified as a bolometer, the new device has a fast response time and, unlike most other bolometers, works over a wide range of temperatures. With a simple design and relatively low cost, this device could be scaled up, enabling a wide range of commercial applications. Researchers describe a graphene-based radiation detector this week in Applied Physics Letters, from AIP Publishing.

The discovery of graphene in 2004 was anticipated to herald a whole new type of technology. "But unfortunately, there are some strong fundamental limitations for this material," said Grigory Skoblin of Chalmers University of Technology in Sweden. "Nowadays, the real industrial applications of graphene are quite limited."

Graphene—composed of single sheets of carbon atoms that form a flat, hexagonal lattice structure—has been used mainly for its mechanical properties.

"But our device shows that more fundamental properties can be used in actual applications," Skoblin said. The new bolometer is based on graphene's thermoelectric properties. Radiation heats part of the device, inducing electrons to move. The displaced electrons generate an electric field, which creates a voltage difference across the device. The change in voltage thus provides an essentially direct measurement of the radiation.

Other devices rely on the generation of electrical current or resistance change by incoming radiation. But measuring changes in current or resistance requires an external power source to generate an initial current. The mechanism is much simpler than in other bolometers, according to Skoblin.

The piece of graphene in the new bolometer is small, so it's one of the fastest bolometers because it heats up and responds quickly. Furthermore, the device remains sensitive to radiation at temperatures up to 200 degrees Celsius. Conventional bolometers typically work only at cryogenic temperatures.

Other researchers have previously made graphene bolometers, with better properties than this new device, but these models contain a double layer of graphene, making them more difficult to scale, Skoblin said.

Another advantage of the new device is its coating. The researchers previously developed a method to coat graphene with a dielectric polymer called Parylene, which offers a good balance of performance and scalability. You can get better performance by coating with hexagonal boron nitride, Skoblin said, but it's hard to acquire and the coating techniques are difficult to scale up. Other studies suggest that a bolometer with hexagonal boron nitride coating would be less efficient.

The prototype bolometer works only with microwave radiation at 94 gigahertz, but future designs will widen the frequency range. Next, the researchers plan to make the device using chemical vapor deposition to grow larger pieces of graphene, paving the way for mass production.

Related Stories

A prototype device called a bolometer measures electromagnetic radiation energy flow based on physical parameter variations of thermosensitive elements as a result of heating by absorption of radiation energy.

(Phys.org) -- Researchers at the Center for Nanophysics and Advanced Materials of the University of Maryland have developed a new type of hot electron bolometer a sensitive detector of infrared light, that can be used in ...

Graphene Flagship scientists based at the University of Groningen, The Netherlands, have created a device based on a blilayer of graphene and boron nitride which shows unprecedented spin transport efficiency at room temperature. ...

Scientists have developed a new method of characterizing graphene's properties without applying disruptive electrical contacts, allowing them to investigate both the resistance and quantum capacitance of graphene and other ...

Researchers from the Graphene Flagship have developed a novel graphene-based infrared (IR) detector demonstrating record high sensitivity for thermal detection. Graphene's unique attributes pave the way for high-performance ...

Recommended for you

A material with atomically thin layers of water holds promise for energy storage technologies, and researchers have now discovered that the water is performing a different role than anyone anticipated. The finding was possible ...

A metabolic research group at KAIST and Chung-Ang University in Korea has developed a recombinant E. coli strain that biosynthesizes 60 nanomaterials covering 35 elements on the periodic table. Among the elements, the team ...

Researchers using powerful supercomputers have found a way to generate microwaves with inexpensive silicon, a breakthrough that could dramatically cut costs and improve devices such as sensors in self-driving vehicles.

Scientists at the University of Alberta have applied a machine learning technique using artificial intelligence to perfect and automate atomic-scale manufacturing, something which has never been done before. The vastly greener, ...

As electronic devices and circuits shrink into the nanoscale, the ability to transfer data on a chip, at low power with little energy loss, is becoming a critical challenge. Over the past decade, squeezing light into tiny ...

0 comments

Please sign in to add a comment.
Registration is free, and takes less than a minute.
Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.